The invention relates to a head-end for a signal distribution system for signals having a wide frequency band and for accompanying signals having a comparatively narrow frequency band, such as the video signal and the sound signal of a television signal, respectively, use being made of digital signals for the signal distribution, comprising a first analog-to-digital converter for the signals having the wide frequency band and a second analog-to-digital converter for the signals having the narrow frequency band.
The invention also relates to a receiver suitable for processing the digital signals generated by the head-end of the signal distribution system, comprising a first digital-to-analog converter for the signals having the wide frequency band and a second digital-to-analog converter for the signals having the narrow frequency band.
Such a head-end and such a receiver for a signal distribution system are inter alia employed in combination with light transmission through optical fibres. The signal-to-noise ratio of an optical transmission path is of such a nature that in practice digital modulation methods having a low number of levels are usually preferred. Simultaneous transmission of, for example, the sound signal and the video signal of a television signal is then possible by multiplexing the sound and the video signals after digitizing. This requires in the head-end a given frame structure together with methods for frame synchronization in the receiver.